The LS50's will sound faster,if you feel the R100's were a little 'heavy', and their better cabinet helps the 'disappear' more. For larger rooms, the R300 dig deeper, play louder, and are clearer due to the dedicated HF/HF UniQ.
And yes to the earlier question of the R100 being used to add into a KHT3005 speaker package, although I would recommend adding the R Series centre at some point too - not only to keep up with the fronts (not that it should be an issue if the the 3005's have been fine in your room), but also to produce a more consistent front soundstage.